Skin cancer of the head and neck with perineural invasion: defining the clinical target volumes based on the pattern of failure.
OBJECTIVE
To analyze patterns of failure in patients with head-and-neck cutaneous squamous cell carcinoma (HNCSCC) and clinical/radiologic evidence of perineural invasion (CPNI), in order to define neural clinical target volume (CTV) for treatment planning.


METHODS
Patients treated with three-dimensional (3D) conformal or intensity-modulated radiotherapy (IMRT) for HNCSCC with CPNI were included in the study. A retrospective review of the clinical charts, radiotherapy (RT) plans and radiologic studies has been conducted.


RESULTS
Eleven consecutive patients with HNCSCCs with CPNI were treated from 2000 through 2007. Most patients underwent multiple surgical procedures and RT courses. The most prevalent failure pattern was along cranial nerves (CNs), and multiple CNs were ultimately involved in the majority of cases. In all cases the involved CNs at recurrence were the main nerves innervating the primary tumor sites, as well as their major communicating nerves. We have found several distinct patterns of disease spread along specific CNs depending on the skin regions harboring the primary tumors, including multiple branches of CN V and VII. These patterns and the pertinent anatomy are detailed in the this article.


CONCLUSIONS
Predictable disease spread patterns along cranial nerves supplying the primary tumor sites were found in this study. Awareness of these patterns, as well as knowledge of the relevant cranial nerve anatomy, should be the basis for CTV definition and delineation for RT treatment planning.
Gluck
Iris
I
Department of Radiation Oncology, University of Michigan, Ann Arbor MI, USA.
Ibrahim
Mohannad
M
Popovtzer
Aron
A
Teknos
Theodoros N
TN
Chepeha
Douglas B
DB
Prince
Mark E
ME
Moyer
Jeffrey S
JS
Bradford
Carol R
CR
Eisbruch
Avraham
A
D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D003391:Cranial Nerves / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D020266:Radiotherapy, Conformal; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D017211:Treatment Failure; D047368:Tumor Burden